Gimbal assembly test system and method

Abstract

Aspects of the present disclosure provide a gimbal assembly test system including: a protective cover affixed to a test surface of a wafer probe card mounted within a gimbal bearing, wherein the protective cover includes an exterior surface oriented outward from the test surface of the wafer probe card; and a recess extending into the exterior surface of the protective cover and shaped to matingly engage a load cell tip therein.

We claim: 
     
       1. A gimbal assembly test system comprising:
 a protective cover affixed to a test surface of a wafer probe card having a plurality of probes and mounted within a gimbal bearing, wherein the protective cover includes an exterior surface oriented outward from the test surface of the wafer probe card, and the protective cover is electrically isolated from the plurality of probes of the wafer probe card; 
 a recess extending into the exterior surface of the protective cover and shaped to matingly engage a load cell tip therein; 
 a positional sensor operatively coupled to the protective cover and configured to determine a first height differential between a first position on the exterior surface and a first reference point; and 
 a first planarity sensor coupled to the positional sensor and contacting the first position on the exterior surface, and a second planarity sensor coupled to the positional sensor and contacting a second position on the exterior surface, wherein the positional sensor is further configured to determine a second height differential between the second position of the exterior surface and a second reference point. 
 
     
     
       2. The gimbal assembly test system of  claim 1 , wherein the recess is laterally offset from a center of the exterior surface and substantially aligned with a position of the load cell tip. 
     
     
       3. The gimbal assembly test system of  claim 1 , further comprising a torque wrench configured to impart a torque against the wafer probe card about a center of the protective cover. 
     
     
       4. The gimbal assembly test system of  claim 3 , wherein the torque wrench is configured to engage the recess and move the protective cover in a predetermined direction. 
     
     
       5. The gimbal assembly test system of  claim 3 , further comprising a controller coupled to the positional sensor and configured to measure a planarity of the wafer probe card based on the first height differential. 
     
     
       6. The system of  claim 1 , wherein each of the plurality of probes is positioned beneath the protective cover. 
     
     
       7. The gimbal assembly test system of  claim 6 , wherein the protective cover includes a rim that affixes the protective cover to the wafer probe card, wherein the rim laterally encompasses the plurality of probes. 
     
     
       8. The gimbal assembly test system of  claim 1 , wherein the exterior surface of the protective cover is oriented substantially in parallel with the test surface of the wafer probe card. 
     
     
       9. A gimbal assembly test system comprising:
 a protective cover affixed to a test surface of a wafer probe card having a plurality of probes and mounted within a gimbal bearing, wherein the protective cover includes an exterior surface oriented outward from the test surface of the wafer probe card, and the protective cover is electrically isolated from the plurality of probes of the wafer probe card; 
 a load cell tip substantially aligned with the protective cover of the wafer probe card, wherein the load cell tip is configured to impart a force against the protective cover and is substantially aligned with a recess extending into an exterior surface of the protective cover, the recess being laterally offset from a center of the exterior surface; 
 a positional sensor operatively coupled to an exterior surface of the protective cover and configured to determine a first height differential between a first point on the exterior surface and a reference point; and 
 a controller operably connected to each of the probe and the positional sensor, wherein the controller measures a planarity of the wafer probe card based on the first height differential, and calculates a correlation between the force against the protective cover and the planarity of the wafer probe card. 
 
     
     
       10. The gimbal assembly test system of  claim 9 , wherein the controller further calculates a gimbaling capacity of the gimbal bearing based on the correlation between the force against the protective cover and the planarity of the wafer probe card. 
     
     
       11. The gimbal assembly test system of  claim 9 , wherein the protective cover is positioned to protect the wafer probe card from an impact from the load cell tip. 
     
     
       12. The gimbal assembly test system of  claim 9 , wherein the load cell tip is shaped to matingly engage the recess within the protective cover. 
     
     
       13. The gimbal assembly test system of  claim 12 , wherein the load cell tip further includes a length-adjustable member positioned within a housing. 
     
     
       14. The gimbal assembly test system of  claim 9 , wherein the load cell tip is coupled to a torque wrench, and wherein the controller is further configured to calculate a torque applied to the protective cover based on the force against the protective cover. 
     
     
       15. A gimbal assembly test system comprising:
 a protective cover affixed to a test surface of a wafer probe card having a plurality of probes and mounted within a gimbal bearing, wherein the protective cover includes an exterior surface oriented outward from the test surface of the wafer probe card, and the protective cover is electrically isolated from the plurality of probes of the wafer probe card; 
 a recess extending into the exterior surface of the protective cover and shaped to matingly engage a load cell tip therein; and 
 a positional sensor operatively coupled to the protective cover and configured to determine a first height differential between a first position on the exterior surface and a first reference point. 
 
     
     
       16. The gimbal assembly test system of  claim 15 , wherein the recess is laterally offset from a center of the exterior surface and substantially aligned with a position of the load cell tip. 
     
     
       17. The gimbal assembly test system of  claim 15 , wherein the protective cover includes a plastic. 
     
     
       18. The gimbal assembly test system of  claim 15 , wherein the protective cover is capable of structurally withstanding an impact imparted by an external device. 
     
     
       19. The gimbal assembly test system of  claim 15 , wherein the protective cover is removably fixed to the test surface by a rim. 
     
     
       20. The gimbal assembly test system of  claim 15 , wherein the protective cover is configured to remain stationary relative to the wafer probe card as the wafer probe card moves within the gimbal bearing.